1. Field of the Invention
This invention relates to a gas heat pump type air conditioning device in which a compression device for circulating a refrigerant is driven by a gas engine as a driving source, and the invention particularly relates to a gas heat pump type air conditioning device which can enhance heating capacity when outdoor air temperature is low.
2. Description of Related Art
An air conditioning device which performs air conditioning such as air cooling and air heating by using a heat pump is provided with a refrigerant circuit including components such as an indoor heat exchanger, a compression device, an outdoor heat exchanger, and a throttling structure. Air cooling and heating indoors is realized by exchanging heat of indoor air and outdoor air temperature by the indoor heat exchanger and the outdoor heat exchanger during the circulation of a refrigerant. Also, in this refrigerant circuit, the receipt of heat during air heating does not rely on only the outdoor heat exchanger, a refrigerant heating device may sometimes by provided for directly beating the refrigerant.
Recently, regarding a driving source for the compression device which is provided in above refrigerant circuit, a driving source employing a gas engine has been developed to replace electric motors which are commonly used. This air conditioning device employing a gas engine is generally called a gas heat pump type air conditioning device (hereinafter called a GHP). By this GHP, because municipal gas or the like which are relatively inexpensive can be used as fuel, thus running cost does not rise because it is different from an electric heat pump provided with compression device using electric motors (hereinafter called EHP), therefore cost can be reduced for consumers.
Also, in a GHP, outstanding air heating effect can be achieved if so-called waste heat such as high temperature exhaust gas exhausted from a gas engine or heat of engine-coolant-water is used as a heat source for the refrigerant during air heating operations, more efficient use of energy is possible as compared with an EHP (electric heat pump). In addition, in this case, the efficiency percentage of energy use of the GHP is 1.2 to 1.5 times higher compared to an EHP. Also, apparatuses above, such as a refrigerant heating device, are not necessary to be installed in the refrigerant circuit if this kind of structure is used.
Additionally, in a GHP, defrosting operations necessary for the outdoor heat exchanging device in air heating can be performed by using the exhaust heat of the gas engine. Generally, the defrosting operation in an EHP is done in such a way that the air heating operation stops and the air cooling operation is temporarily performed to defrost the outdoor heat exchanging device. In this case, because cold air flows into the room, comfortableness inside the room is deteriorated. In contrast, in a GHP, continuous air heating operation is possible because of the above condition, and problems occurring in the case of an EHP do not arise.
As mentioned above, in a GHP, the exhaust heat such as high temperature exhaust gas exhausted from gas engines or waste heat of engine-coolant-water is introduced to a heat exchanging device such as an, exhausted gas heat exchanging device or water heat exchanging device during air heating operation; thus, collecting exhaust heat is possible by using such exhaust heat as a heat source for the refrigerant, outstanding air heating capacity can be obtained differently from EHP.
In conventional GHPs, engine-coolant-water is heated by exhaust heat during the flowing of exhaust gas exhausted from the gas engine through an exhaust gas heat exchanging device; in addition, the engine-coolant-water absorbs heat while flowing inside a water jacket of the gas engine and cooling the water jacket of the gas engine; thus the temperature of the engine-coolant-water rises.
If such high temperature engine-coolant-water which collected the exhaust heat from the gas engine is sent to a water heat exchanging device, the refrigerant can be heated by heat of the engine-coolant-water; thus, the refrigerant can be evaporated sufficiently by a cooperation between a water heat exchanging device and an outdoor heat exchanging device even in an air heating operation when outdoor air temperature is low.
However, there is a limit to the above improvement of the heating capacity achieved by collecting exhaust heat; thus, in other words, there is a limit to the amount of exhaust heat which is collectable; therefore, there has been a limit on the improvement of air heating capacity when the outdoor air temperature is low. In particular, in a case such as that above when a GHP is used in cold areas where the outdoor air temperatures considerably, the amount of heat absorbed from outdoor air temperature in the outdoor heat exchanging device decreases extremely; thus, it is difficult to obtain necessary amounts of heat to sufficiently evaporate the refrigerant.
Accordingly, in order to enable a gas heat pump type air conditioning device to demonstrate sufficient air heating capacity even in an air heating operation in cold temperature are so as to provide a comfortable indoor environment, it is necessary to obtain sufficient amount of heat to evaporate the refrigerant when the outdoor air temperature is low, and to improve the air heating capacity higher.
This invention was made in consideration of above conditions. Thus an object of this invention is to provide a gas heat pump type air conditioning device in which air heating capacity during low outdoor air temperatures can be improved to be higher. Also, an object of this invention is to provide a gas heat pump type air conditioning device which can exhibit sufficient air heating capacity even when the outdoor air temperature is low.
In order to solve the above problems, the invention has the following construction.
In a gas heat pump type air conditioning device according to the first aspect of this invention, a refrigerating cycle is formed by circulating the refrigerant by a compression device for which the driving source is a gas engine, waste heat exhausted from the gas engine is collected in engine-coolant-water, and the refrigerant is heated by the engine-coolant-water in order to enhance the heating capacity, a bypass channel is formed which is provided with a channel change switching device in an engine-coolant-water system downstream of the gas engine, and an engine-coolant-water heating device is provided in the bypass channel.
According to such a gas heat pump type air conditioning device, a bypass channel is formed which is provided with a channel change switching device in an engine-coolant-water system downstream of the gas engine, and an engine-coolant-water heating device is provided in the bypass channel; thus, it is possible to raise the temperature of the engine-coolant-water by heating it, if necessary, to heat the refrigerant by high temperature engine-coolant-water in order to expedite the evaporation, and to enhance the air heating capacity when the outdoor air temperature is low.
In this case, the heating device should preferably heat the engine-coolant-water by combusting the gas fuel in the same way as above gas engine; thus, it is possible to heat using inexpensive gas fuel by using a similar fuel supplying system as the gas engine.
Also, in the above gas heat pump type air conditioning device, the above heating device should preferably operate when the outdoor air temperature detecting device detects a temperature which is lower than the predetermined value, and during the warm up operation of the above gas engine.
Because of this, even if air heating operation is operated during low outdoor air temperature, because the heating capacity for the refrigerant in the water heat exchanging device decreases, thus air heating operation for realizing the comfortable indoor environment by maintaining the refrigerating cycle is possible.
In an engine-coolant-water heating device according to the second aspect of this invention, an engine-coolant-water heating device is provided in the engine-coolant-water system of the gas heat pump type air conditioning device for heating the engine-coolant-water flowing after cooling the gas engine.
This engine-coolant-water heating device comprises: a frame body which is provided with a ventilation fan; pipes which are provided in the frame body and conduct the engine-coolant-water; a combustor which is provided in the frame body; a fuel supplying system which supplies fuel and air to the combustor at a predetermined ratio, wherein the engine-coolant-water which flows in the pipes is heated by the combusting device.
According to such an engine-coolant-water heating device, the engine-coolant-water heating device comprises a frame body which is provided with a ventilation fan, pipes which are provided in the frame body and through which flow the engine-coolant-water, a combustor which is provided in the frame body, a fuel supplying system which supplies fuel and air to the combustor at a predetermined ratio, and the engine-coolant-water which flows in the pipes is heated by the combustion device; thus, it is possible to heat the engine-coolant-water flowing in the pipes efficiently by the combustion device to raise the temperature.
In this case, the above fuel should preferably be the same fuel as the fuel used in the gas engine; accordingly, it is possible to heat with inexpensive gas fuel by using a similar fuel supplying system as in the case of the gas engine.
Additionally, the most favorable engine coolant heating device is a so-called gas water boiler; thus, an ordinary product found on the consumer market can be used without any modification.
Because of this, even in air heating operation during low outdoor air temperature, because the amount of thermal energy in the refrigerant in the water heat exchanging device increases, air heating operation for realizing the comfortable indoor environment by maintaining the refrigerating cycle is possible.
In an operating method for a gas heat pump type air conditioning device according to the third aspect of this invention, a gas heat pump type air conditioning device in which a bypass channel provided with a channel change switching device is formed in an engine-coolant-water system of the downstream side of the gas engine, an engine-coolant-water heating device is provided in the bypass channel, comprises steps of: forming a refrigerating cycle by a circulation of the refrigerant using a compression device of which driving source is the gas engine; collecting waste heat exhausted from the gas engine to engine-coolant-water, heating the refrigerant by the engine-coolant-water; and operating the engine-coolant-water heating device so as to heat the engine-coolant-water during air heating operation when outdoor air temperature is lower than a predetermined value and during warm up of the gas engine.
According to such an operating method for a gas heat pump type air conditioning device, the engine-coolant-water heating device operates so as to heat the engine-coolant-water during air heating operation when the outdoor air temperature is lower than a predetermined value or during warm up of the gas engine; thus, the temperature of engine-coolant-water is raised and air heating capacity during low outdoor air temperature is improved. Also, because the rise of the temperature of engine-coolant-water is expedited, the time for warm up operation can be shortened.
Because of this, air heating capacity is enhanced during low outdoor air temperature because the temperature of the engine-coolant-water becomes high, and the time for warm up operation can be shortened because increase of the temperature of engine-coolant-water is expedited.
In an operating method for a gas heat pump type air conditioning device according to the fourth aspect of this invention, a refrigerating cycle is formed by a circulation of refrigerant using a compression device of which driving source is a gas engine, exhaust heat exhausted from the gas engine is collected to engine-coolant-water, the refrigerant is heated by the engine-coolant-water so as to enhance air heating capacity, a bypass channel provided with a channel change switching device is formed in an engine-coolant-water system of the downstream side of the gas engine, an engine-coolant-water heating device is provided in the bypass channel.
In the operating method of a gas heat pump type air conditioning device, the engine-coolant-water heating device operates a ventilation fan while stopping supplying fuel to a combustor during air cooling, and the engine-coolant-water heating device is used as a radiator for the engine-coolant-water flowing in pipes.
According to such an operating method for a gas heat pump type air conditioning device, the engine-coolant-water heating device operates a ventilation fan while stopping supply of fuel to a combustor during air cooling, and the engine-coolant-water heating device is used as a radiator for the engine-coolant-water flowing in pipes; thus, it is possible to enhance the capacity of the radiator in operating conditions in which the outdoor air temperature is high, and to prevent the overheating of the gas engine.
Because of this, the occurrence of the overheating in the gas engine GE can be prevented by enhancing the capacity of the radiator for operating conditions in which the outdoor air temperature is high.